On the Magnet, by William Gilbert

Chap. xviii. An armed Loadstone does not endow an excited piece of Iron with
greater vigour than an unarmed.

uppose there are two pieces of iron, one
of which has been excited by an armed loadstone, the other by one unarmed; and let there be applied to one of them
another piece of iron of a weight just proportional to its strength, it is manifest that the remaining one in like
manner raises the same and no more. Magnetick versoria also touched by an armed loadstone turn with the same velocity
and constancy towards the poles of the earth as those magnetized by the same loadstone unarmed.